Is addon domain config really this limited?

I just set up my primary domain with a new host who allows addon domains. Got it working and now I'm preparing to set up a second as an addon to the primary.

First I get the error that DNS must be configured before creating the addon. No problem for a brand-new domain, but what if I'm trying to transfer an *existing* domain to this account? Anyone who's transferred a domain between hosts knows you basically build a working mirror of the site on the new host, THEN switch DNS, right? You want to make sure there are no disruptions in availability.

Fine, I figure I can still upload my files, create databases, get the site working. But then I go to create my email addresses. No luck - CPanel will only let me create addresses for my primary domain since the addon hasn't been created yet. So basically, it seems like I have to switch DNS, *then* create all my necessary email addresses, forwarders etc, just hoping beyond hope that no one sends me email between the time of the DNS switch and the time I get the addresses created? CPanel frustrates me enough by not providing a way to batch-create addresses or forwarders. Combined with these addon domain limitations it's a recipe for lost email!